power will increase at 15degrees. torque will move down RPM (-) as timing increases (generalization)... as torque moves down, power will increase and also come in earlier (RPM wise)
as far as air/fuel, it will need to be retuned and just checked to make sure all is well. Tune for 11.5-12.0 A/F ratio for a nice street fuel curve.
"As the Z32 gets older and decreases in value it becomes affordable by lower income and often less desirable people whose tastes reflect their personality and social standing.- Marshall 17:37:05 10/10/03